Nanostructured bulk Mg + MgO composite synthesized through arc plasma evaporation and high pressure torsion for H-storage application

•A method combining arc plasma evaporation and high pressure torsion is developed.•Bulk Mg based nano-composite containing dispersed MgO is successfully prepared.•Bulk Mg composite shows better H-storage properties over the ultrafine Mg powder.•MgO improves the hydrogen sorption kinetics of the bulk Mg nano-composite.

A nanostructured Mg based bulk material containing Mg nano-grains and dispersed nanosized MgO was prepared through arc plasma method followed by high pressure torsion (HPT). In comparison to pure Mg ultrafine powders prepared using only arc plasma method, the hydrogenation enthalpy was slightly increased and the absorption activation energy was reduced through the HPT treatment. The structure refinement and the fragmentation of the MgO layer induced by the HPT account for the improved hydrogen sorption thermodynamic and kinetic properties.